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Frequent Questions-Residential Lights
How can I reduce my lighting cost?
Though the energy used by a single light is small, if you use energy-efficiency practices with all of your lights, the savings can add up. To reduce lighting costs, consider:
  • Turning the lights off when you leave a room.
  • Installing timers, time clocks or photocells to ensure that exterior lights are turned off at the appropriate time.
  • Replacing incandescent lights with ENERGY STAR®-qualified compact fluorescent lights. They can reduce lighting costs by up to 75 percent and last up to eight times longer.
  How much can I save? It is difficult to estimate for residential lighting usage. However, you can get some idea when you compare replacement of 100W incandescent lamp with equivalent light output 23W compact fluorescent lamp.
Lamp Type
100W Incandescent
23W Compact Fluorescent
Purchase Price
Life of the Lamp
750 hours
10,000 hours
Number of Hours Burned per Day
4 hours
4 hours
Number of Lamps Needed
About 6 over 3 years
1 over 6.8 years
Total Cost of Lamps
Total Cost of Electricity (5c/kWh)
Total Cost over 3 years
Total savings over three years with the compact fluorescent light  is $10.36, which is almost equal to the initial cost of the lamp. That means that the compact fluorescent pays for itself within three years.
How much will it cost?
Compact fluorescent lights are a bit expensive, but their low energy use and extended life span make them economically attractive. You can also take advantage of rebates offered by your local utility. A replacement of a 60 watt incandescent lamp with a 15 watt compact fluorescent may yield up to $9 of annual energy cost savings (based on 4,000 operating hours and $0.05/kWh).
I bought several compact fluorescent lamps, that went bad after just a few months. What can I do to protect myself against such event occurring again?
Shop carefully to avoid lower-cost, lower-quality lamps. When you buy, ask a salesperson about the store´s return policy and any consumer complaints they have received. Stick with products from reputable manufacturers. They may be more expensive than others, but their well-researched design ensures top quality service.
How can I find out more about residential lighting?
Call your local utility representative or call Oregon Department of Energy at (503) 378-4040.
Should I replace the incandescent lamps at home with compact fluorescent lamps?
Yes. With the cost of electricity on the rise, all incandescent lamps that operate for more than three hours a day should be replaced with compact fluorescent lamps. Compact fluorescents are three to four times more efficient than incandescent sources and last many times longer. The color rendering of many newer compact fluorescents are now much improved and are almost indistinguishable from the incandescent sources. There are even compact fluorescents designed for dimming capability to work with your existing incandescent dimmers.
Does frequent switching a fluorescent light on and off shorten its life?
Unfortunately, to some extent, yes. It does not mean however, that you should keep your lights on all the time whether the room is occupied or not. As a simple rule of thumb, you should always turn the lights off if they will not be used for more than five minutes. You may want to consider installing occupancy sensors that will automatically turn the lights on when person´s presence is detected and off when lack of such detection is sensed after a preset period of time.
Will dimming an incandescent or halogen lamp save energy?
Halogen lamp is a type of incandescent lamp, so they both fall into the same category. Dimming of incandescent lamp saves energy to some degree, but the light output drops much faster than the energy saved because the lamp still uses a lot of energy to generate infrared heat. If less light is acceptable, consider use of lower wattage lamp, or use more efficient source like a compact fluorescent. For example, dimming a 75 watt incandescent lamp by 25 percent will still use 66 watt. You may want to use a 50 watt light instead, or install an 18 watt compact fluorescent.